The purpose of this proposal is to replace the 17 year-old Kratos MS5O magnetic sector high resolution mass spcctrometer at Purdue University with a state of the art magnetic sector high resolution mass spectrometer. The Kratos MS50 is the only high resolution mass spectrometer at Purdue, and its age as well as the heavy demands placed on it cause it to fail on a regular basis, thus jeopardizing the research progress of a large number of NIH-funded investigators across campus. Besides being more reliable than the MS50, a new magnetic sector high resolution mass spectrometer will offer the advantages vs. the MS50 of extended mass range, eletrospray ionization capabilities, and it will provide a suitable platform for HPLC-MS. The new instrument will be located in the Department of Medicinal Chemistry and Molecular Pharmacology and will be incorporated into the present Campus-wide Mass Spectrometry Center (CWMSC). As such, it will serve over 70 different research groups across campus located in 20 academic departments. The mass spectrometer funded by the present application will be administered by an existing policy which applies to the current Kratos MS50 instrument. The Mass Spectrometry Oversight Committee will meet with the appropriate sales representatives, review the specifications and performance of the candidate instruments and will make the final selection. In addition, this committee will select test samples, examine the test sample results and ultimately coordinate the installation of the instrument. The Director of the Campus-wide Mass Spectrometry Center, the Departmental Mass Spectrometry Operator and the Electronics Technician will work with the Installation Engineer to become as proficient as possible in the maintenance and operation of the new instrument. The instrument will be supported financially by the Department of Medicinal Chemistry and Molecular Pharmacology, the Department of Chemistry, the Purdue Cancer Center, and by charges to users based on the time required to perform the service. The charge rate will be set by the Department Head in consultation with the Faculty Representative of the Department responsible for the Mass Spectrometry Laboratory and the Director of the CWMSC.